Cutter guard



A. WHITE CUTTER GUARD May 26, 1931.

3 Sheets-Sheet 1 Filed Aug. 29, 1929 /Nl EN 70R. WWLZ: 5r

ATTORNEY A. WHITE CUTTER GUARD May 26, 1931.

a QM T 0 N W 4 w 5 W 1 M l; I. W .un lmflh idmw W W F Y B 3 2 1- Eu W 7m QR P 1/ w 2 3 5 f 4 a q. 3 a 1 w 2 GD MWM 9 or fl \M|||||liuuhnhunuufl nnn hufiumullfi I: HAW. 2 3 o I 2 W A 6 2 1 a i 3 N 0m r ATTORNEY A. WHITE CUTTER GUARD May 26 Filed Aug. 29, 1929 3Sheets-Sheet 5 //V VENTORI ATTORNEY Patented May 26, 1931 UNETED STATESPATENT OFFHCE ALPHONZO WHITE, or wmonnnbon, M

ASSACHU'SETTS, ASSIGNOR TO BAXTER D.

WHITNEY & 8011, INC., 0F WINCHENDON, MASSACHUSETTS, A CORPORATION OFMASSACHUSETTS CUTTER GUARD Application filed August 29, 1929. Serial No.389,223.

This invention relates to movable guards for cutters, and moreparticularly to guards for protecting the rotating cutters of shapers.

Shapers having a work supporting table and a vertical power-drivenspindle to which a cutter is secured are extensively used in the woodworkin industries. These cutters are driven at high speed usually inexcess of 5000 revolutions per minute so that if a cutter breaks orworks loose from the spindle it will be thrown outwardly by centrifugalforce with the speed of a bullet, thus endangering the workmen near themachine.

As long as the work is in contact with the cutter, or is in closeproximity thereto, the work itself will protect the machine attendant toa degree from the flying parts, in case the cutter breaks, but he is notaiforded this protection from flying parts when the work is Withdrawn.

The present invention therefore relates to a cutter guard mounted formovement to and from the cutter enclosing position, and

in mechanism for automatically shifting the guard. A

It has been proposed heretofore to employ a solenoid to move the cutterguard away from the cutter as the work is presented to the cutter, butthe guard which is relatively heavy should be quickly removed from thecutter asthe work is presented to the cutter. This requiring the use ofa large powerful solenoid which is expensive to manufacture.

An important feature of the present invention therefore resides in acutter guard provided with fluid operated means for automaticallyshifting the guard as the Work is presented to or removed from thecutter, and a more specific feature of the invention resides in meansoperable by compressed air for quickly withdrawing the cutter guard asthe work is presented to the cutter and for holding the guard in itsretracted position until the Work is removed from the cutter.

A further-feature of'the invention resides in a cylinder into which airis introduced under pressure to move a piston in a direction to withdrawthe guard, and in adjustable means for varying the speed at which theair enters V or leaves the cylinder to thereby vary the speed at whichthe cutter guard is shifted.

Still a further feature of the invention resides in valve operatingmeans located near the cutter and passage of the work to and from thecutter.

Other features of the invention and novel combination of parts inaddition to the above will be hereinafter described in connection withthe accompanying drawings Which illustrate good practical forms thereof.

In the drawings Fig. 1 is a perspective view of the upper portion of adouble spindle shaper provided with the guards of the present invention,one guard being raised and the other lowered.

Fig. 2 on an enlarged scale is an end view of the shaper of Fig. 1 withparts in section;

Fig. 3 is a vertical sectional view through a bumper to be described;

' Fig. 4 on a further enlarged scale is a perspective view of a shapercutter and the associate guard;

Fig. 5 is a top plan view of the shaper table showing modified means forcontrolling the guard operating valve.

Fig. 6 is a verticalsectional View taken on the line 6-6 of Fig. 5;

Fig. 7 is an enlarged sectional view through the guard actuating valve;

Fig. 8 is a side elevation of the valve of Fig. 7 provided with meansfor regulating the exhaust; and

Fig. 9 is a vertical sectional view through adapted to be actuated bythe double spindle shaper of well known construction.

The shaper shown consists of a supporting base 10 provided with the worksupporting table 11, and extending upwardly through the table are theusual spindles 12 and 13 having the cutters 14. The spindles are drivenin opposite directions at high speed by belts or motors as desired, andthe work rests upon the table 11 while it is being acted upon by acutter. Usually the work such as 15 which is to be presented to a cutteris bolted or otherwise secured to a form 16 that rests upon the tableand the outer periphery or profile of the form 16 may act as a guide fordetermining the depth of cut, in a well known manner.

hen a shaper spindle is provided with a long or large cutter the spindlemay vibrate to an objectionable degree while the cutter acts upon thework, and it is therefore common to provide each spindle with anoverhead steady bearing for the spindle top. This steady bearing whenused is mounted upon a post 1' positioned back of a cutter and having abase plate 18 that may be rigidly secured to the table 11 by bolts 19.

The construction so far described is well known in the art, but isutilized in carrying out the present invention to support the cutterguard and guard operating means which will now be described.

Each of the rotating cutters 14 is provided with a guard 20 which ispreferably curved as shown so that it will practically surround thecutter, and the guard may be formed of sheet metal. In the constructionshown each guard 20 is mounted for vertical sliding movement so that itmay be lowered about a cutter to protect the latter, or raised above thecutter to permit engagement of the work with the cutter. The guards 20are conveniently supported for vertical sliding movement by providingthe post embracing collars 21 and 22 having the projecting arms 23 andthese collars may be rigidly secured to the usual bearing supportingposts 17 by tightening the clamping bolts 24, 25. The arms 23 supportthe guide rods 26, and the guard 20 is provided at its inner face withthe rod receiving brackets 27 which slidably secure the guard 20 to theguide rods 26.

When a guard 20 is in its lowered position as shown to the left in Fig.1, the low 1' portion of the guard is spaced only a slight distance fromthe face of the table so that it will completely protect the cutter, andthe guard may be supported in this lowered position by the brackets 27resting upon the lower arms 23.

In the embodiment of the invention illustrated the weight of the guard20 is relied upon to move the guard downward to its cutter protectingposition when the means for holding it elevated is released. Thearrangement is such that the guard normally remains in the loweredposition in which it is shown at the left in Fig. 1. It is thereforenecessary to raise the guard before the work is engaged with the cutter,and an important feature of the present invention resides in means forautomatically raising the guard as the work approaches the cutter, andfor lowering the guard as the work is moved away from the cutter.

This is accomplished, in accordance with the embodiment of the inventionillustrated, by employing a cylinder having a piston for operating theguard 20, and valve controlled means is provided for admitting air underpressure to the cylinder and for exhausting it therefrom. Thearrangement is such that the valve that shifts the guard is controlledby the movement of the work toward and from the cutter.

The guard 20 may be raised by a rocking lever 28 one end of which issecured by a pivot pin 29 to a projection 30 that extends upwardly fromthe upper collar 22. The lever 28 has the frontwardly extending arms 31to which the guard 20 is connected by the links 32.

The rocking lever 28 is elevated to lift the guard 20 by an operatingrod 83 which extends upwardly through the hollow post 17 and downwardlythrough an opening in the table 11. The upper end of the rod 33 ispivotally secured to the lever 28 by a bolt 34 and the lower end of therod 33 is connected to a piston rod 35 that extends into a cylinder 36which is supported by a bracket 37 beneath the table 11. The piston rod35 has a piston 38 adapted to slide within the bore of the cylinder, andsecured to the under face of the piston 38 is a cup-shaped washer 89(see Fig. 9).

Air under pressure is supplied to the lower end of the piston 36 by thepipe 40. The arrangement is such that when air is forced into thecylinder 36 the piston 38 will be forced upwardly to act through the rod33 and bracket 38 to lift the guard 20, and the guard will be held inits elevated position as long as the air pressure is maintained in thecylinder. As soon as the air pressure within the cylinder 86 is relievedthe guard will drop to its cutter protectin position.

The upward movement of the guard is conveniently limited by a rod 41extending upwardly from the upper collar 22 and this rod is providedwith a yielding bumper adapted to be struck by the portion 42 of thebracket 28. The bumper (see Fig. 3) consists of a hollow casing 43having threaded engagement with the rod 41 for adjustment lengthwise ofthe rod and inthe casing 43 is a coiled spring 44 which exerts acontinuous downward pressure upon the sliding element 45. The casing 43is secured in the desired position of adjustment along the rod 41 bytightening the lock nut 46.

In order to raise and lower the guard 20 by the mechanism so fardescribed, air under pressure is supplied from any suitable source bythe pipe 47 which is connected to the casing 48 of the control valve bythe pipe 49 and the flow of air to the valve casing 48 is preferablycontrolled by a needle valve 50 that may be adjusted as desired to varythe speed at which air will be forced into the cylinder 36 to lift theguard 20.

The valve casing 48 is connected to the cylinder 36 by the pipe 40 andthe construction of the valve casing 48 is best shown in Fig. 7 whereinit will be seen that the valve casing has a vertical plunger 51 which isnormally held elevated by the coiled spring 52. The plunger 51 has areduced portion 53 and an upper portion 54 and to the upper portion theoperating button 55 is secured by means of a pin 55.

The valve casing may be mounted in a hole in the table 11 so that theupper end of the casing 48 will be flush with the upper face of thetable, and the button 55 extends upwardly a slight distance above theface of the table and is adapted to be engaged and held depressed by thelower face of the form 16 as long as the work is adjacent the cutter 14.

As long as the valve plunger 51 is elevated as shown in Fig. 7, airsupplied to the lower port 56 by the pipe 49 is confined in this port bythe plunger, but when the plunger is depressed so that the reducedportion 53 thereof is opposite the port 56, then the air under pressurewill pass from pipe 49, port 56 and port 57 to the pipe 40 and throughthe latter into the cylinder 36 to elevate the piston 38, and thispressure upon the piston will be maintained as long as the button 55 isdepressed, thus holding the guard 20 elevated.

When the form 16 is removed from the work the plunger 51 will moveupwardly under the action of the spring 52 to the position of Fig. 7.This will close port 56 and permit the air in the cylinder 36 to escapethrough the pipe 40, port 57 and upper port or ports 58.

In some cases it may be desirable to employ a single exhaust port 58 andprovide this port with a valve 59 adapted to be ad jueted to vary thespeed at which air may escape from the cylinder 36 to thereby vary thespeed at which the guard 20 will be lowered.

While air has been described herein as the actuating medium it will beunderstood that various fluids either liquids or gases may be employedto this end, and that various forms of valves may be employed to controlthe action of the fluid upon the guard shifting means.

It may be desirable to depress the valve button 55 from a plurality ofpoints adjacent the cutter,

and this may be accomplished by providing the pivoted lever or yoke 60which may be pivotally mounted at 61 beneath the table 11 so that anintermediate portion of this lever will rest the lever may have thespaced pins 62 that extend upwardly through holes in the table so thatifpressure is exerted downwardly upon any one of the pins 62 the lever60 will be depressed to depress the button 55. WVhen this constructionis employed the valve casing 48 may be supported by a bracket 63.

It willbe seen from the foregoing that the movement of the guard 20 toand from the cutter protecting position is readily controlled bycompressed air, and that the speed at which the guard is raised orlowered may *be varied as desired by changing the adjustment of thevalves 50 and 59.

It should be noted that the guard supporting brackets or collars 21 and22 are positioned near the opposite ends of the post 17 and that theguard operating rod 33 extends upwardly through the hollow post. Thisconstruction is important since it leaves the intermediate portion ofthe post 17 free to receive the cutter s-teadying guard as heretofore,and as a result the post 17 may perform the double function ofsupporting the usual cutter steadying device and the cutter guard.

What is claimed is 1. In combination with a shaper having a worksupporting table, a power driven cutter and .a hollow cutter-steadyingpost; a cutter guard. a frame fastened to said post for supporting theguard for sliding movement to and from the cutter protecting position, aguard operating lever pivotally supported by said post and connected tothe guard, a rod extending upwardly through said post to operate thelever, a fluid operated piston mounted below the table to actuate therod, and a valve for controlling the operating fluid supplied to saidpiston.

2. In combination with a shaper having a work supporting table, a powerdriven cutter and a hollow cutter-steadying post; a cutter guard, aframe fastened to said post for supporting the guard for slidingmovement to and from the cutter protecting position, a rod extendingupwardly through said post and operatively connected to the guard, afluid operated piston for shifting said rod, and a valve for controllingthe operating fluid supplied to the piston and positioned to be actuatedby presenting work to the cutter.

3. In combination with a shaper having a work supporting table, a powerdriven cutter and a hollow cutter-steadying post; a cutter guard. aframe fastened to said post to support the guard for sliding movement toand from the cutter protecting position, a guard operating leverpivotally supported by said post and connected to the guard, a rodslidable within said hollow post and connected upon the button 55 and tothe lever to actuate the guard, stop mechanism for limiting the upwardmovement of the guard including a yielding buffer and means forsupporting the same in different positions of adjustment, a fluidoperated piston mounted below the table to actuate the rod, and a valvefor controlling the operating fluid supplied to the piston andpositioned to be actuated by presenting Work to the cutter.

In testimony whereof, I have signed my name to this specification.

ALPHONZO WHITE.

